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LEQ: What is Macroevolution?

LEQ: What is Macroevolution?. Evolution on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction. Evolutionary Novelties . Complex structures evolve in increments from simpler versions – having the same basic function

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LEQ: What is Macroevolution?

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  1. LEQ: What is Macroevolution? Evolution on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction.

  2. Evolutionary Novelties • Complex structures evolve in increments from simpler versions – having the same basic function • Natural selection acts on structures in such as way as to improve it in the context of its current use • For example – the eye evolved from a cluster of light sensitive cells. From the very beginning these cells enable the organism to gather information about its environment. With each successive change organisms were able to gather more and more useful information about their environment

  3. Evolutionary Novelties – Evolution of the Eye • http://www.pbs.org/wgbh/evolution/library/01/1/quicktime/l_011_01.html • http://learn.genetics.utah.edu/content/variation/eye/

  4. Evolutionary Novelties • Name two other examples from your book…. • Evolution of feathers – dinosaurs to birds • http://www.youtube.com/watch?v=zVEjVIo-jro • Flippers of penguins

  5. EVO - DEVO • http://www.youtube.com/watch?v=14yxfot5sq8 • http://www.youtube.com/watch?v=kG6nDDSE_4k

  6. Evolutionary Trends do not Imply Evolution is Goal Directed • Trends in evolution have been identified: • Horse – fossil record shows evolution of horse moving from 3 toes to one; small size to large; browsers to grazers • Human – fossil record shows human evolution moving from smaller skull to larger; simple brain to more complex • REGARDLESS OF TRENDS - Evolution is the result of interactions between organisms and their current environments • If the environment changes, the current evolutionary trend may cease or even reverse itself • Blind Cave Fish – cannot see – flesh grows over the eyes

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